Three Texas landowners and an environmental group filed the first lawsuit on Friday challenging President Donald Trump’s national emergency declaration aimed at freeing up billions of dollars to build a wall along the US border with Mexico, the consumer advocacy group Public Citizen said.

The lawsuit, brought in federal court in the District of Columbia, claims the south Texas landowners were told by the US government that it would seek to build a border wall on their properties if money for the project were available in 2019, Public Citizen said in a statement. Trump declared a national emergency earlier in the day to bypass Congress to use money from the Pentagon and counter drug efforts to fulfill his promise of completing the border wall. The president said immigrants entering the US illegally were invading the country.

The announcement was immediately met with resistance from members of Congress.

House Speaker Nancy Pelosi and several Democratic state attorneys general already have said they might go to court. California is also likely to sue Trump, the state attorney general said Friday.

The American Civil Liberties Union (ACLU) also announced its intention to sue less than an hour after the White House released the text of Trump’s declaration.

Two main issues

The coming legal fight seems likely to hinge on two main issues: Can the president declare a national emergency to build a border wall in the face of Congress’ refusal to give him all the money he wanted and, under the federal law Trump invoked in his declaration, can the Defense Department take money from some congressionally approved military construction projects to pay for wall construction?

The Pentagon has so far not said which projects might be affected. But after weeks of publicly ruminating whether to act, Trump’s signature on the declaration set in motion a quick march to the courthouse. Trump relied on the National Emergencies Act of 1976, which Congress adopted as a way to put some limits on presidential use of national emergencies. The act requires a president to notify Congress publicly of the national emergency and to report every six months. The law also says the president must renew the emergency every year, simply by notifying Congress. The House and Senate also can revoke a declaration by majority vote, though it would take a two-thirds vote by each house to override an expected presidential veto.

Beyond that, though, the law doesn’t say what constitutes a national emergency or impose any other limits on the president.

California and the American Civil Liberties Union are also poised to sue

The broad grant of discretion to the president could make it hard to persuade courts to rule that Trump exceeded his authority in declaring a border emergency. “He’s the one who gets to make the call. We can’t second-guess it,” said John Eastman, a professor of constitutional law at the Chapman University School of Law.

Courts often are reluctant to look beyond the justifications the president included in his proclamation, Ohio State University law professor Peter Shane said on a call organized by the liberal American Constitution Society. But other legal experts said the facts are powerfully arrayed against the president. They include government statistics showing a decades-long decline in illegal border crossings as well as Trump’s rejection of a deal last year that would have provided more than the nearly $1.4 billion he got for border security in the budget agreement he signed Thursday. Opponents of the declaration also are certain to use Trump’s own words at his Rose Garden news conference Friday to argue that there is no emergency on the border.

“I could do the wall over a longer period of time,” Trump said. “I didn’t need to do this, but I’d rather do it much faster.”

No emergency

California Attorney General Xavier Becerra and Gov. Gavin Newsom, both Democrats, told reporters that there is no emergency at the border and that Trump doesn’t have the authority to make the declaration.

“No one in America is above the law, not even the president of the United States,” Becerra said. “The president does not have power to act frivolously.” Trump declared a national emergency earlier in the day to bypass Congress to use money from the Pentagon and counter drug efforts to fulfill his promise of completing the border wall. The president said immigrants entering the US illegally were invading the country.